Process and apparatus for electroplating



March 3, 1931. K. w. SCHWARTZ 1,794,487

PROCESS AND APPARATUS FOR ELECTROPLATING Filed June 26, 1928 2 Sheets Sheet 1 March 3, 1931. K. w. SCHWARTZ 1,794,487

PROCESS AND APPARATUS FOR ELECTROPLATING Filed June 6, 1928 2 Sheets-Sheet 2 Fig 5.

Patented Mar. 3, 1931 uNrr o s'ra'rns PATENT OFFICE.

KEVIE W. SCHWARTZ, OF NEW YORK, N. Y., ASSIGNOB, BY MESNE ASSIGNMENTS, TO UNITED OHROMIUM, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF DEL AWARE PROCESS API'ARATUS FOR ELECTROPLATING application-filed. June 23, 1928. serial No. 288,438.

This invention relates to a process and apparatus for electroplating, and more particularly for progressi ely' or successively plating large areas and other areas where i conditions are such that progressive plating is necessary or desirable, and provides .1111- provements therein. An invention of this general type is shown in my U. S. Patent #1,720,354, granted July 9, 1929.

The invention provides an improved apparatus, particularly useful for plating the inside of hollow vessels, and further provides meansfor current distribution to the anode structure.

The invention further provides an improved means and method of edecting cleaning of the surface to be plated, by hydrogen released by the electric current.

Other features of improvement will be set forth in connection with the accompanying description.

An embodiment of the invention is illustrated in the accompanying drawings, wherem:

Figure 1 is a vertical longitudinal section of a large still, such as used in oil cracking, and having set up therein and thereon the apparatus for electroplating.

Figs. 2, 3 and 4 are sections-on the lines IIH, Ill-HI and lV-IV, Fig. 1, respectively.

Fig. 5 is a top plan view of certain of the electrical connections shown at theextreme upper portion, Fig. 1.

Fig. 6 is a section on the line VI.VI, Fig. 1.

Figs. 7 8 and 9 are detail views on an enlarged scale, Fig. 7 being an enlargement of the parts shown in vertical section 1n the upper part of Fig. 1; Figs. 8 and 9 be ng enlarged views showing the connection between the shaft 40 and the conduits 30 and 33 carrying the electrical conductors leading to the anodes, Fig. 8 being a cross-section on hne VIIIVIII Fig. 9, and Fig. 9 being a vertical section on line IX--IX Fig. 8.

Referring to said drawings, numeral 10 designates an article to be plated, here shown as a large still or reaction chamber used in the process of cracking 011. As an example,

such stills have a height of 40 feet, and a diameter of 10 feet. These reaction chambers are usually provided with restricted openings 11, 12 at top and bottom, of a few feet in diameter. Many of these reaction chambers are set u in installations, and it is desirable to He a le to electro-deposit the coating metal on the vessel 10in, situ.

The preferred coating metal 'is chromium. Any suitable solution for electrodepositing the chromium may be used. ll prefer, however, the method and solution disclosed in Fink Patent 1,581,188, granted April 20, 1926.

In electrodepositing chromium from chromic acid baths, there is relatively large disengagement of hydrogen which is released from the cathode surface as a gas, and the current densities used are relatively large.

' To attempt to electrodeposit chromium simultaneously over the entire inner surface of a vessel having the given dimensions of the vessel 10, would, under ordinary conditions, require the use of about 100,000 amperes. Generators this size would be inordinately large, and, in any event, it would in most cases be preferable to use generators of less ampere rating.

Furthermore, if it were attempted to'electrodeposit chromium on the entire surface at once, the disengagement of hydrogen would be'so great as, under ordinary conditions, to interfere with the deposition being successfully effected over the entire surface.

In making use of the present invention, deposition is carried out on a part of the inner surface of the vessel 10, at a time, and this electrodeposit is progressively extended over or around the entire surface.

Numeral 20 designates an anode comprising electrically-independent sections, two such sections, 21, 22, being here illustrated. 25 indicates asecond anode comprising electrically-independent sections 26, 27. Additional anodes similar to 20, 25 may, if desired, be employed.

Means are provided for moving the anodes axially of the vessel, and also for rotating said anodes.

The means for moving the anodes preferably comprises a tube or the like 30, passing into the vessel through its neck 11 and ex- I tending upwardly beyond the solution level.

At the lower end of the tube there is conveniently a T 31, to which is connected a hollow arm 33, the said arm 33 carrying at its outer end one of the anode sections, 22 for example. The anode sections 21, 26, and 27 are similarly connected.

The tube 30 and arm 31 preferably enclose an insulated electrical conductor 35 -which carries current to one of the anode sections, and thereb di ering currents and current densities to e obtained between the anode sections and the cathode surface (inner surface of the vessel 10).

The tube 30 is preferably made in several longitudinal sections as shown, connected by couplings 37. As the anode sections are'extended further axially down into the vessel,

, section after section may be added.

The means for rotating the anodes (and sections)- preferably comprises a shaft 40'. This shaft 40 extends into the vessel, preferably through theopening 11, and is preferably supported at its upper end by a key 42 resting against a plate 43, which latter rests upon a sleeve 44 having teeth meshing with a worm 46, by which it is driven. The weight of the shaft 40 is sustained by the plate 43 on which the key 42. passing through the I insulating plates said shaft 40, rests. The lower end of the shaft is preferably steadied and centered by means of a ball and socket connection 48. A temporary cross-piece 50 attached to the walls of the vessel 10 serves to support the lower. part of the connection 48, and insulators 52 are provided for insulating the shaft from the vessel 10.

The shaft 40 is rotated by the worm 46 (through the sleeve 44, plate 43 and key 42, as hereinbefore explained) and this rotary motion is imparted to the anode sections through collars 55 having a key connection to the saidshaft 40 as shown at 56, Fig. '2, the T31 to which the arm 33 carrying an anode section, is connected, having an extension 57 which is fastened to the said collar 55. This extension 57 is conveniently a pin threaded into the T and clamped between 58, 59,-the said plates 58, 59 thereby insulating the anode andits supporting parts from the shaft 40 and'collar 5.5 sliding thereon. I

The collars 55, together with the shaft 40, serve as guiding means for the anode sections in their axial movements, and preserve the centered position of said sections with respect to the vessel 10. Suitable rings for collecting current which is led to the anode sections, are provided. Two of these, 61, 62, are showrn These are preferably connected to the plate 43 (being suitably insulated therefrom and insulated from each other, as shown), and turn with the said plate 43. These rings 61, 62 are hollow and permit of the tubes 30 which support the anode sections extending upwardly therethrough, the said plate 43 being provided with suitable openings 65 through which the said tubes 30 may pass. Connection between the conductors 35 leading to the anode sections 22 (and others) to the rings 61, 62 is made accessible and convenient by providingterminal extensions 71 72 from the inside of the rings 61, 62, and the ends of the conductors 35 which proect through and beyond the rings 61, 62 1s made to the terminal extensions 71, 72

through heavy clamps 74, 75. These clamps 74, 75 are accessible and may be readily removed and replaced for connecting the terminal extensions to different anode sections,

and also in making the changes, necessary for effecting the axial displacement or movement of the anode sections.

The connection of the anode sections to independent collector rings permits of current at difierent strength and potential being led in through said collector rings.

An overflow basin 80 is preferably rovided at the upper end of the vessel 10, w ich permits of the solution level being above the vessel 10. From this basin 80 the overflow passes to a tank 82, and circulation is provided by forcing the solution from vessel 82 into the bottom of the tank and causing it to overflow at the upper end from the basin 80. A pump 84 connected to the tank 82 and lower end of vessel 10 is here shown. 86 indlcates an interchanger through which temperature regulation may be effected.

Operation To efiect plating of the vessel 10, curren is led to the anode sections 21, 22 for example, through the rings 61, 62 and conduc-- position. The shaft 40 is rotated through worm 46, plat-s43 and key 42, and through the key connection therewith of the collar 55 carries the anode sections 21, 22 around with 1 the said shaft 40 as it is rotated. The cur rent passes between the anode and the cathode and electrodeposition is effected on the cathode surface opposite the anode sections, and extends progressively around the anode (in required thickness of plate, it is shifted axially to another, and rotated in that position, completing another band of electrodeposit,

. and thisis repeated until the plating of the I face are desirable.

inside surface, or so much thereof as is desired, is completed.

llhe anode sections 26 and 27 are preferably shaped to the underside of the top of the vessel 10. In practice, it has been found that, particularly in plating the upper top portion of the vessel 10, currents of difierent densities for difierent portions of this sur- The independent elec trical connections of the sections 26, 27 permit of a flow of current from one of these sections to the cathode which is difi'erent than that which flows from the other. For example, a greater current density is passed between the anode section 27 and the opposite portion of the cathode 10 than between the anode section 26 and the part of the cathode surface opposite it.

ln'adjusting the axial positionpf the anode sections 21, 22 for example, sections of the tube 30 arelremoved, or added, and joined by unions 37, and the ends of the conductors projecting therethrough are connected through suitable clamps 74, 7 5 to the terminal extensions 71, 7 2 connected to the collector rings 61, 62.

Method According to my invention, 1 may effect cleaning of the surface by the current in conjunction with deposition. in carrying this into practice, particularly with a chromic acid plating solution, I lead current to one of the-anode sections, 21 for example, at a current density which eilects plating on the cathode surface opposite thereto. To the other anode section 22 I lead current at a density which isinsuflicient to effect a plate, butwhich is suiticient to release hydrogen on the cathode surface opposite thereto. This hydrogen evoltion lifts particles'oit any foreign matter from the anode surface and also eflects reduction of oxides present on the cathode surface. Whenthe anode sections are shifted, the'anode section 21 is shifted What is claimed is:

' 1. Apparatus for plating successive portions of a large area, comprising an anode, means for moving said anode comprisin tubular means extending outside of the ath, conductors in" said tubular means connected to said anode, and protected from the bath by said tubular means, and means for guiding said anode structure in its movement to its different positions of use.

2. Apparatus for plating successive portions of a large area, comprising an anode, a tubular arm attached to said anode, means for moving said anode comprising tubular means extending outside of the bath and connected with said tubular arm, conductors in said tubular arms and tubular means, protected thereby from the bath solution, and connected to said anode, and means for guid ing said anode structure in its movement to itsdiflerent positions of use. L

3. Apparatus for plating successive portions of a large area, comprising an anode,

means for moving said anode comprising tubular means extending outside of the bath, conductors in said tubular means connected to said anode, and protected from the bath by said tubular means, and means for guiding said anode structure in its movement to its different positions of use, said guiding means comprising a shaft, and a sliding collar thereon.

4. Apparatus forplating successive portions of a large area, comprising an anode, means for moving said anode comprising means extending outside of the bath, conductors in said tubular means connected to said anode, and protected from the-bath by said tubular means, and means for guiding said anode structure in its movement to its diii'erent positions of use, said guiding means comprising a shaft, a sliding collar thereon, a non-rotating connection between said shaft and collar, and means for rotating said shaft and thereby said collar and anode.

5. Apparatus for plating successive porcomprising a plurality of electrically independent sections, means for moving said anode, means for supplying current independently to said anode sections, and

means for supplying current at a density to produce gassing at one portion of said area to be plated, and at a plating density at another portion of said area.

6. Apparatus for plating successive portions of a large area comprising an anode comprising a plurality of electrically independent sections, means for moving said anode, and means for supplying current at independent voltages to said sections.

7. Apparatus for plating successive portions of a large area, comprising an anode, means for rotating said anode, and means for moving said anode to different axial positions, said last named means being rotatable with the anode. Y

8. Apparatus for plating successive portions of a large area, comprising an anode, means for rotating said anode, means for moving said anode to different axial positions, and means for guiding said anode in its movement to different axial positions, said last two named means being rotatable with said anode. v

9. Apparatus for plating successive portions of a large area, comprising an anode, means for rotating said anode,means for moving said anode to different axial )ositions, and means for guiding said ano e in. its movement to different axial positions, said guiding means comprising a shaft, and a sliding collar thereon.

10. Apparatus for plating successive portions of a large area, comprising an anode, means for rotating said anode, means for moving said anode to different axial positions, means for guiding said anode in its movement to different axial positions, said guiding means comprising a shaft, a sliding collar thereon, a non-rotating connection between said shaft and collar, and means for insulating said shaft and guiding means from said anode.

11. Apparatus for plating successive por-,

tions of a large area, comprising an anode, means for rotating said anode, means for moving said anode to different axial positions, means for guiding said anode in its movement to difierent axial positions, said means comprising a shaft, a sliding collar thereon, a non-rotating connection etween said shaft and collar, and means for insulating said shaft and guiding means from said anode, said means for moving said anode axiallycomprising tubular means connected with said collar, a tubular connection from said collar to said anode, and a conductor passing to said anode through said tubular means, collar, and tubular anode connection.

12. Apparatus for plating successive portions of a large area, comprising an anode, nrcans for rotating said anode, means for moving said anode axially, said rotating means comprising a shaft and means for rotating said shaft, a driving connection between said anode and shaft, said means for driving said shaft com rising a tubular sleeve concentric with sai shaft, said' means for moving said anode axially comprising a part extending through said tubular sleeve and connected to said anode.

13. Apparatus for plating successive por-- tions of a large area,-com rising an anode,

means for rotating said ano e, means for moving said anode axially, said rotating means comprising a shaft'and means for rotating said shaft, a driving connection between said anode and shaft, said means for driving said shaft comprising a tubular sleeve concentric with said shaft, said means for moving said f anode axially comprising a part extending through said tubular sleeve and connected to said anode, a tubular conducting ring concentrio with said driving sleeve, a conductor from said ring to said anode, said conductor extending inside said ring and through said sleeve.

14. Apparatus for plating successive portions of a large area, comprising an anode having a plurality of sections, means for rotating said anode, means for moving said anode sections axially, said rotating means comprising a shaft and means for rotating said shaft, a driving connection between said an ode and shaft, said means for driving said shaft comprising a tubular sleeveconcentric with said shaft, said means for moving said anode sections axially comprising tubular parts extending through said sleeve, and'conductors leading to said anode sections passing through said tubular parts.

15. Apparatus for plating successive portions of a large area, comprising an anode having a plurality of sections, means for rotating said anode, means for moving said anode sections axially, said rotating means comprising a shaft and means for rotating said shaft, a driving connection hetween said anode and shaft, said means for driving said shaft comprising a tuloular sleeve concentric with said shaft, said means for moving said anode sections axially comprising tubular parts extending through said sleeve, and conductors leading to said anode sections passing through said tubular parts, tubular conducting rings concentric with said driving sleeve, said conductors being connected to said rings.

l6, Apparatus for plating successive portions of large area, comprising an anode having a plurality of sections, means for rotating said anode, means for moving said anode sections axially, said rotating means comprising a shaft and means for rotating said shaft, driving connections between said anode and shaft,- said means for driving said shaft comprising a tubular sleeve concentric with said shaft, said means for moving said anode sections axially comprising tubular sectional parts extending through said sleeve alongside said shaft.

17. Apparatus for plating successive portions of large area, comprising an anode having a plurality of sections, means for rotating said anode, means for moving said anode sections axially, said rotating means comprising a shaft and means for rotating said shaft, driving connections between said anode and shaft, said means for driving said shaft comprising a tubular sleeve concentric with said shaft, said means for moving said anode sections axially comprising tubular sectional parts extending throughsaid sleeve alongside said shaft, tubular conducting rings concentric with, and having driving connection with, said driving sleeve, terminal extensions I from said rings parallel with said tubular sec- 1 passing current from an anode section to a portion of a cathode surface at a current dentional parts, and conductors leading to said anode sections through said tubular sectional parts and connected to said terminalextensions.

18. A method of electroplating comprising sity to deposit metal, and passing an independent current from another anode section to another portion of said cathode surface in the same bath at a current density to produce gassing to effect cleani In witness whereof, fiiave hereunto signed my name. KEVE w. SCHWARTZ. 

